1. Field of the Invention
The present invention relates to a computer-readable storage medium, an image processing apparatus, an image processing system, and an image processing method, for detecting a predetermined capturing target from an image captured by capturing means.
2. Description of the Background Art
Conventionally, there is a technique of detecting a predetermined capturing target from an image captured by capturing means such as a camera (a captured image). For example, Non-Patent Literature 1 states that in augmented reality technology, an image recognition process is performed on a marker included in an image captured by a camera. Non-Patent Literature 1 states that connected regions are extracted by binarizing the captured image using a fixed threshold, and regions of appropriate sizes and shapes are selected, from among the extracted connected regions, to be marker candidates. Then, the marker is detected by performing pattern matching on the marker candidates.    [Non-Patent Literature 1] Hirokazu Kato, Mark Billinghurst, Koichi Asano, Keihachiro Tachibana, “An Augmented Reality System and its Calibration based on Marker Tracking”, Journal of the Virtual Reality Society of Japan, vol. 4, no. 4, 1999
The detection method of a marker described in Non-Patent Literature 1 cannot necessarily detect a marker with high accuracy or a small processing load in various states (e.g., a bright state; a dark state; the state where part of the marker is hidden by, for example, a user's finger; the state where the marker does not face the camera in a full-face manner; and the state where a strong light is reflected by the marker).
In addition, the detection method of a marker described in Non-Patent Literature 1 cannot prevent a slight deviation of the position of the detected position of the marker.